Need an OC guide for the nVidia 8800GTS

[Mutley]

Hi all,

Does anyone know of a good guide for overclocking the nVidia 8800GTS 640MB?
Or perhaps could give me some pointers?

I have an XFX 8800GTS 640MB.
Default core clock is 513Mhz and default memory is 792Mhz.

I'm trying to improve performance in Company of Heroes (although I'm not convinced the graphics card is the bottle neck). For context, the motherboard is an Abit IP-35 Pro, the CPU an E6600 (at stock speeds), with 2GB of Crucial PC6400 RAM.

I use RivaTuner for monitoring purposes, and using that I've been messing with the graphics card core and memory clock.

I've been using RTHDRIBL with FRAPS and the artifact scanner in ATITool to observe the impact.
So far I've had the core clock up to 680Mhz, and the memory to 950 with no apparent problems. FPS clearly increases, and there are no aritifacts in ATItool.

This bothers me, because it seems like a large OC with no visual defects. RivaTuner sets the OC limit to 770 on the core and 1190 on the memory (not sure where those values come from mind).

Am I missing something, or are the OCs I'm applying reasonable?

TIA

Mut.

[chuckskull]

You've got all the basics sorted. 625/900-950(mem chips vary by manufacturer) is the average OC in my experience. So you're doing quite well. AtiTool can only give you an indication of problems. It's not the be all and end all though.

I recommend a few runs through 3Dmark and a few hours gaming on something graphics intensive; COH is good for that, try an FPS too if you got one they seem to be the best for finding problems. If it's all good no crashes or artifacts you're done.

Edit: Rivatuner gives 30% leeway over default iirc. Thats where those limits come from.

[Mutley]

Thanks Chuckskull.

Do you know how to change the limits on RivaTuner? Somewhere in the power settings I suspect...

Reading around, I see mention that the default core on 8800GTS 640Mb is 580Mhz, rather than the 513 I see on mine. Is that right? I'm using RivaTuner to detect the clock settings.

What should I be looking for when OC'ing both core and memory? Increase each by the same percentage, or the same Mhz, or......should I OC core first, then do memory (I would have thought this is not the best way of approaching it).

As far as ATItool, I'm only really using it to see if it can detect artifacts - am I right in assuming this will work? (Says so on guru3D). I'm concerned that I may push the limits on my card too far and do some damage.

EDIT: This is my card.
From this I can see the stock core is 500Mhz and memory is 1600Mhz (800 actual), so that makes sense with what I'm seeing.

Thanks!

[chuckskull]

I've not used Rivatuner in a while so I'm not sure how to remove the limits sorry. Though tbh unless you have about £500 of cooling gear you didn't mention it would take a VERY good card to hit the limits on air cooling.

The artifact scan on ATiTool is good, but it's best not to stick to one test(I've had cards that can run 3dmark all day then lock up on certain games and vice versa). Also you'll want to leave the scan running 30mins to an hour at least. Heat is what will limit your OC, it takes a while for heat to build up. Remember you might be playing games for hours on end sometimes.

Overclock GPU and mem individually, find the limits of each and then try both together.

My advice at the moment would be to give the card a good thrashing at your current OC. IF there are no artifacts and the temps are reasonable, try pushing a little further.

[Mutley]

Thanks again.
Good advice. I'm going to do some poking around on this tomorrow.
Looks like I've got quite a good OC on this card without even trying at the moment, using stock cooling.